File extensions – definition and basic information


File extensions are the integral parts of the files that are on each computer. Often, when working on a computer, we encounter a wide range of files, such as docx, ppt, part, mp3 or rmvb. We realize that they are there – but we often do not know what they are for on our computer.

File extension, also known as the filename extension is a suffix added to the name of a computer file, usually consisting of a number of characters placed after the last dot in the filename, which gives us information about its coding. In other words a file extension is a file format. It allows the operating system (e.g. Windows) to recognize what program it should try to open the file.

In the table below you will find a random selection of popular file extensions.


File extension The full name of the file Category

ASP file extension

Active Server Page

Web Files

AZW file extension

Amazon Kindle eBook File

eBook Files

BAT file extension

DOS Batch File

Executable Files

CAB file extension

Windows Cabinet File

System Files

DAT file extension

Data File

Data Files

DDS file extension

DirectDraw Surface

Raster Image Files

DEM file extension

Video Game Demo File

Game Files

DOC# file extension

Microsoft Word Document

Text Files

GPX file extension

GPS Exchange File

GIS Files

MID file extension

MIDI File

Audio Files

MOV file extension

Apple QuickTime Movie

Video Files

MSG file extension

Outlook Mail Message

Text Files

ROM file extension

N64 Game ROM File

Game Files

RPM file extension

Red Hat Package Manager File

Compressed Files

VCF file extension

vCard File

Data Files